This research plan is designed to evaluate the potential of using synthetic peptides representing portions of viral structural proteins as vaccines against the virus. Using automated synthesizers, peptides of about 15 amino acids in length will be synthesized which correspond to regions of a 267 amino acid segment of the feline panleukopenia viral proteins. This segment is known from our previous work to contain immunogenic determinants which raise neutralizing antibodies to both FPV and its closely related variant canine parvovirus (CPV). These peptides will be used to immunize animals and sera from these animals will be tested for antibodies which: 1) bind to intact virus, and 2) are able to neutralize the virus in a tissue culture infectivity assay. If a peptide is found which fulfills these criteria, it will be tested for its ability to protect dogs and cats from challenge by live virus, or in other words, to act as a vaccine. The results will be directly compared to immunization with inactivated or attenuated FPV viral vaccines as well as FPV viral coat protein vaccines synthesized in bacteria through recombinant DNA technology. If this approach to immunization against CPV is effective, it will be applied to other pathogens as well. Vaccination with synthetic peptides should eliminate many of the problems associated with conventional vaccines, such as spread of disease by incompletely inactivated or attenuated organisms or side reactions against contaminants in the vaccine preparations. Synthetic peptides will introduce a much needed element of precision and specificity into the design of future vaccines.